Obesity with chronic inflammation affects a large and growing population. This population has a high risk for developing cardiovascular disease and diabetes and frequently develops metabolic syndromes associated with insulin resistance. Recently, adiponectin and other adipokines have been discovered as fat cell hormones that control glucose metabolism. Both type and location of fat cells are important. Obesity produces additional adipocytes which secrete adiponectin into the blood, helping muscle cell metabolism of fats and glucose. Some overweight patients become insulin resistant. In this case, adipocytes stop producing adiponectin. Levels of adiponectin in the blood are decreased under conditions of obesity, insulin resistance and Type 2 diabetes. Methods exist for measuring adiponectin levels in subjects for the prognosis of these and other disease states. Measurement of adiponectin levels, however, has proven to be a weak indicator of disease. A need exists for better methods of monitoring disease states associated with abnormal adipocyte activity. The present invention provides this and other needs.
Adiponectin Receptor 1 (ADIPOR1) is a seven transmembrane G protein coupled receptor (GPCR). See, for example, WO 01/012662 and WO 01/090304. Many medically significant biological processes are mediated by signal transduction pathways that involve G-proteins [Lefkowitz, Nature 351, 353-354 (1991)]. Certain extracellular messengers (ECM), which are peptide fragments from the C-terminal of ADIPOR1, have diagnostic value in human blood. Their usefulness was confirmed using a polyclonal antibody with a mass measuring SELDI-TOF immuno-affinity method. Those inventions are the subject of related application WO 2007/120,311, which is incorporated herein by reference.